Medical delivery pumps are commonly used in delivery systems such as, for example nasogastric, esophagastric, and abdominal feeding systems for feeding flowable, and more typically liquid compositions enterally or intravenously to patients. Many of these pumps include disposable cassettes or peristaltic tubing (otherwise sometimes referred to as a lumen) that inserts into the pump and through which the liquid flows for delivery to the patient.
It is important that such pumps are capable of accurately controlling the flow of liquid to the patient. For peristaltic pumps, in one example, the mechanical dimensions and material properties of the tubing (which is typically a silicone material) are major factors that bear on the delivery accuracy of the pump (e.g., on the accuracy of the volumetric flow). More specifically, tube dimensions such as inner diameter, wall thickness and tube length, and material properties such as the durometer (which generally affects the compressibility of the tube) and Young's modulus (which generally affects the stretchability of the tube), are key properties that affect the delivery accuracy of the pump.
Such tubing is typically extruded, and historically it has been challenging to consistently reduce the delivery accuracy error (e.g., the difference between a predetermined or desired volumetric or dosage delivery through the tube and an actual volumetric or dosage delivery through the tube) to less than about seven percent and more particularly to less than about five percent with an extruded tube. In particular, it is difficult to maintain tight tolerances on the material characteristics of some tubing materials such as silicone. These variations in silicone characteristics (e.g., durometer, elasticity, etc.) cause the delivery accuracy of the pump to vary from one manufacturing lot to another.
A need therefore exists for a tube manufacturing method and system that results in a formed tube sufficient to reduce the delivery accuracy error from one manufacturing lot to another.